Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
69 words
An improved PbSnTe sputtered unannealed sensor having photoconductive response exceeding those of intrinsic PbSnTe sensors, said sensor comprising in combination: (a) a monocrystalline heat resistant substrate; and (b) a thin sputtered unannealed monocrystalline film on said substrate and having the formula Pb 1-x Sn x Te where x is in the range from 0.0 to about 0.3, said film having a cutoff wavelength between about 6μm and about 15μm.
Claim 2
Dependent Claim
69 words
An improved PbSnTe sputtered unannealed sensor having photoconductive response exceeding those of intrinsic PbSnTe sensors, said sensor comprising in combination: (a) a monocrystalline heat resistant substrate; and (b) a thin sputtered unannealed monocrystalline film on said substrate and having the formula Pb 1-x Sn x Te where x is in the range from 0.0 to about 0.3, said film having a cutoff wavelength between about 6μm and about 15μm.
Claim 3
Dependent Claim
52 words
The improved sensor of claim 1 wherein said sensor has a photoconductive responsivity of up to about 10 3 volts per watt at 77° K, a detectivity of up to about 1.5 × 10 10 cm-Hz 1/2 /W above the 1/f noise frequency, and a response time less than about 100 nanoseconds.
Claim 4
Dependent Claim
48 words
The improved sensor of claim 1 wherein said film has a thickness optimized for highest quantum efficiency and lowest detector noise and wherein said film has a low carrier concentration, a predetermined carrier type and high Hall mobility, said film being stable over a substantial period of time.
Claim 5
Dependent Claim
16 words
The improved sensor of claim 3 wherein x has a value of between 0 and 0.3.
Claim 6
Dependent Claim
25 words
The improved sensor of claim 3 wherein said carrier concentration is in the range of about 10 14 -10 16 cm -3 at 77° K.
Claim 7
Dependent Claim
18 words
The improved sensor of claim 5 wherein said carrier concentration approaches 10 14 cm -3 at 77° K.
Claim 8
Dependent Claim
27 words
The improved sensor of claim 5 wherein the noise value in said detector approaches Johnson noise and is less than about 5 nV/Hz 1/2 at 77° K.
Claim 9
Dependent Claim
18 words
The improved sensor of claim 3 wherein said film has a thickness between about 1μm and about 2μm.
Claim 10
Dependent Claim
21 words
The improved sensor of claim 1 wherein said substrate is selected from the group consisting of calcium fluoride and barium fluoride.
Claim 11
Dependent Claim
12 words
The improved sensor of claim 9 wherein said substrate is calcium fluoride.
Claim 12
Dependent Claim
12 words
The improved sensor of claim 9 wherein said substrate is barium fluoride.
Claim 13
Dependent Claim
264 words
An improved thin film photoconductive sensor comprising, in combination: (a) a heat resistant insulating substrate of a selected single crystal material; and (b) a thin sputtered unannealed monocrystalline film on said substrate comprising Pb 1-x Sn x Te where x is in the range from 0.0 to about 0.3, said film having a cutoff wavelength between about 6μm and about 15μm, a photoconductive responsivity of up to about 10 3 V/watt at 77° K with a detectivity of up to about 1.5 × 10 10 cm-Hz 1/2 /W above the 1/f frequency, and a response time less than 100 nanoseconds, said film thickness being about 1-2μm so that the 1/f noise frequency is below about 1 KHz, said film having been sputtered in the presence of a dopant gas selected from the group consisting of nitrogen and oxygen, at a partial pressure in the case of oxygen of up to about 5 × 10 -6 torr and at a partial pressure in the case of nitrogen of up to about 1 × 10 -5 torr, and an argon environment at total pressures in the range from 0.5 to 5μm onto said substrate at a substrate temperature of between about 220° and about 350° C at a film growth rate between about 0.1-3.0μm/hr, said substrate temperature and film growth rate having been selected to provide a monocrystalline film of desired composition, a substrate bias voltage of between about +30 and -30 volts having been applied during said sputtering, whereby minimum carrier concentration of selected type, maximum mobility and improved responsivity are provided for the film.
Claim 14
Dependent Claim
264 words
An improved thin film photoconductive sensor comprising, in combination: (a) a heat resistant insulating substrate of a selected single crystal material; and (b) a thin sputtered unannealed monocrystalline film on said substrate comprising Pb 1-x Sn x Te where x is in the range from 0.0 to about 0.3, said film having a cutoff wavelength between about 6μm and about 15μm, a photoconductive responsivity of up to about 10 3 V/watt at 77° K with a detectivity of up to about 1.5 × 10 10 cm-Hz 1/2 /W above the 1/f frequency, and a response time less than 100 nanoseconds, said film thickness being about 1-2μm so that the 1/f noise frequency is below about 1 KHz, said film having been sputtered in the presence of a dopant gas selected from the group consisting of nitrogen and oxygen, at a partial pressure in the case of oxygen of up to about 5 × 10 -6 torr and at a partial pressure in the case of nitrogen of up to about 1 × 10 -5 torr, and an argon environment at total pressures in the range from 0.5 to 5μm onto said substrate at a substrate temperature of between about 220° and about 350° C at a film growth rate between about 0.1-3.0μm/hr, said substrate temperature and film growth rate having been selected to provide a monocrystalline film of desired composition, a substrate bias voltage of between about +30 and -30 volts having been applied during said sputtering, whereby minimum carrier concentration of selected type, maximum mobility and improved responsivity are provided for the film.
Claim 15
Dependent Claim
22 words
The improved sensor of claim 12 wherein said substrate material is selected from the group consisting of calcium fluoride and barium fluoride.
Claim 16
Dependent Claim
13 words
The improved sensor of claim 13 wherein said substrate material is calcium fluoride.
Claim 17
Dependent Claim
13 words
The improved sensor of claim 13 wherein said substrate material is barium fluoride.